It has been known to detect the deficiency of operational capability of vacuum switching vessels which can be caused, for instance, by a leak and the poorer vacuum resulting therefrom by utilizing the fact that there is an exceptionally large amount of heat which is developed when the contacts of such a defective vessel are opened; this heat is used for release purposes. In this connection, devices in the fashion of fusible link triggers, propellant charges and similar means have been described which are in thermally-conducting contact with a part of the vacuum switching vessel having a relatively small temperature time constant. In an arrangement of this kind, devices or apparatus are therefore attached directly to the vacuum switching vessels.
The instant invention is likewise concerned with an arrangement for detecting deficient operational capability of vacuum switching vessels which causes a signal to be given and/or a protective device to respond if a fault occurs.
It is an object of the invention to detect deficient operation without making contact and to therefore make it unnecessary to make changes in the vacuum switching vessels.